Panelboards have been known heretofore which accept circuit breakers of various pole widths and frames in intermixed arrangements. For example, a panelboard may have a plurality of single-, two- and three-pole industrial frame breakers mounted thereon in varying arrangements, the industrial frame breakers having by example a 13/8 inch pole-to-pole spacing. Where it is desired to include branch lighting circuits using residential frame circuit breakers having for example 3/4 inch pole-to-pole spacing on the same panelboard, it has been a common practice to provide a separate residential frame lighting circuit panel attached in series above or below the larger industrial frame panel. This arrangement generally restricts the location on the panelboard of the smaller residential frame circuit breakers to be all in one area which restricts flexibility for the later addition of breakers of a different size to the panelboard. In some instances, industrial frame panelboards have incorporated specific branch circuit connectors which directly convert that panelboard to branch lighting circuit capabilities, but the dead front or cover structure for the panelboard dictates that the smaller residential frame circuit breakers also be collectively located in a common area on the panelboard.